JP2023552716A - Conditioning of superabrasive grinding tools - Google Patents

Abstract

In a method of machining a workpiece in a tooth grinding machine having a grinding tool 320 with ceramic bonded abrasive grains made of superabrasive material, the grinding tool is first dressed. The dressed grinding tool is then conditioned to provide the desired wear condition of the grinding tool. The pre-toothed workpiece is then machined using a dressed and conditioned grinding tool. Conditioning prevents undesirable cutting behavior of the grinding tool, which can lead to thermal damage to the edge zone of the workpiece. Conditioning is performed by conditioning kinematics, which differ from machining kinematics and can correspond to dressing kinematics. Conditioning tools 416 and 425 having a basic shape different from the basic shape of the workpiece are used for conditioning. [Selection diagram] Figure 2

Description

The present invention relates to a method for machining a workpiece in a gear grinding machine using a grinding tool configured as a profile grinding wheel or a grinding worm and containing vitrified bond grinding grains made of superabrasive material, in particular cBN. A gear grinding machine designed to carry out the method.

In gear grinding, it is possible to choose between different specifications of grinding tools. In addition to dressable corundum tools with vitrified bonds and non-dressable cBN tools with electroplated bonds, dressable cBN tools with vitrified bonds are also known. Vitrified bond cBN tools exhibit greater flexibility than electroplated bond tools due to the dressable bond. Due to the high performance cBN cutting particles, vitrified bond cBN tools can achieve high material removal rates. As a result, the volume machined between two dressing operations can be increased compared to corundum tools.

The disadvantage of vitrified bonded cBN tools is that they lead to undesirable grinding-in behavior (Research report FVA 778 I, retrieved November 16, 2020 from www.fva-net.de IGF No. 18580 N). The term "cutting behavior" is understood to refer to the phenomenon that, when using vitrified bonded cBN tools, thermal damage to the edge zone of the heat-treated workpiece (so-called grinding burn) can occur immediately after dressing. . For example, during interrupted profile grinding of gear wheels in which individual tooth grooves are ground one after the other, thermal damage to the edge zone is often inscribed in the first machined tooth groove after dressing. There are various approaches to explain this undercut behavior (insufficient chip space, exposed bonds, flattening of cBN grains).

To overcome this problem, the prior art proposes conditioning the grinding tool by "breaking in" it after dressing. Two measures have been proposed regarding this. According to a first strategy, after dressing, the first tooth groove or the first workpiece is machined with a reduced infeed and/or a reduced axial feed rate. This strategy is expensive to implement and can result in the properties of the initially machined workpiece deviating from those of the subsequently machined workpiece. According to a second strategy, after dressing, the sacrificial workpiece or workpieces are first machined and then discarded. This strategy is time consuming and expensive.

US Pat. No. 5,003,302 discloses a method for conditioning a superabrasive grinding tool, in which a sacrificial member is made a plurality of cuts after dressing the grinding tool. The geometry of the sacrificial part corresponds to the geometry of the workpiece that is subsequently machined using a grinding tool.

U.S. Patent Application Publication No. 2005/272349

The aim of the invention is to avoid the need for machining sacrificial workpieces when using grinding tools containing vitrified bonded superabrasive abrasive grains without introducing thermal damage to the edge zone of the workpiece at the beginning of the tool life. The object of the present invention is to disclose a method that ensures uniform machining of a workpiece.

This object is achieved by the method of claim 1. Further embodiments are defined in the dependent claims.

A method is therefore proposed for machining a workpiece in a gear grinding machine using a grinding tool comprising vitrified bonded abrasive grains made of superabrasive material, in particular cBN. This method is
a) dressing the grinding tool;
b) conditioning the dressed grinding tool to provide a desired wear condition of the grinding tool, the gear grinding machine performing conditioning kinematics;
c) machining a pre-toothed workpiece having a predetermined basic shape using a dressed and conditioned grinding tool, the gear grinding machine performing machining kinematics;
including.

The process is characterized in that the conditioning kinematics are different from the machining kinematics.

Therefore, in contrast to the prior art, the sacrificial workpiece is not machined by machining kinematics for conditioning, but the conditioning is done by moving the conditioning tool relative to the grinding tool by special conditioning kinematics. executed. In particular, the conditioning kinematics may correspond to dressing kinematics that may be used to dress the grinding tool. Therefore, a conditioning tool having a different basic shape from the workpiece, in particular the basic shape of the dressing tool, can be used for conditioning. For example, if the workpiece is gear-shaped, it is preferable that the conditioning tool also not be gear-shaped. Alternatively, the conditioning tool can be, for example, a rotating disk-shaped conditioning tool, or a stationary, eg, pin- or tooth-shaped conditioning tool.

A variety of advantages can be obtained by using different kinematics than machining kinematics for conditioning. In particular, conditioning can be performed much more on-target since exercise sequences can be specifically adapted to achieve optimal conditioning results. For example, the infeed of the conditioning tool radially relative to the axis of rotation of the grinding tool, the rotational speed of the grinding tool and, if applicable, of the conditioning tool, the direction of action (up-cut or down-cut direction) and whether the conditioning tool Technical parameters such as the profile feed rate and the degree of overlap when not carried out in line contact along the complete machining profile can be specifically adjusted. The use of conditioning tools with separate conditioning kinematics can also reduce the unproductive idle time that would otherwise occur after conditioning to replace sacrificial workpieces with machined workpieces. . Also, unlike sacrificial workpieces, conditioning tools can be used multiple times. This significantly reduces material consumption.

The following definitions are used herein.

In this specification, "superabrasive material" is understood as a material whose micro-Vickers hardness at room temperature is greater than that of corundum. This class of superabrasive materials includes cubic boron nitride (cBN) and diamond, among others. cBN is particularly important for hardening pre-toothed steel workpieces because, unlike diamond, it has no chemical affinity for typical gear materials. In this regard, the invention particularly relates to a grinding tool in which the abrasive body is formed by vitrified bonded cBN particles.

“Edge zone thermal damage” or “grinding burn” of a workpiece is defined as a damage pattern as specified in ISO 14104:2017-04. Verification of whether there is thermal damage in the edge zone is carried out by the surface temper etching method specified in ISO 14104:2017-04. Thermal damage to the edge zone of the workpiece as defined herein exists if the workpiece does not meet class FA/NB2 after type 3 etching according to ISO 14104:2017-04.

As used herein, the term "basic shape" refers to the geometric shape of an object excluding minor differences in dimensions. For example, two cylindrical gears with the same helical angle, the same module, and the same number of teeth are considered to be objects with the same basic shape, even if the cylindrical gears have different tooth thicknesses, tooth profiles, or tooth flank lines, for example. Conversely, a disc without the teeth of a cylindrical gear or a fixing pin, tooth or rod is considered an object with a different basic shape than a cylindrical gear.

As used herein, the term "dressing" or "truing" refers to, on the one hand, creating or restoring the desired geometry of the grinding tool, and, on the other hand, by engaging the rotating grinding tool with the dressing tool; Grinding is understood to mean the process by which a tool is sharpened.

As used herein, the term "conditioning" means specifically providing a desired wear condition. During conditioning, the geometry of the grinding tool produced during dressing is preferably no longer changed. Conditioning can serve, in particular, to remove the binder between the abrasive grains after dressing in order to partially expose the abrasive grains.

The terms "dressing kinematics", "conditioning kinematics" and "machining kinematics" refer to the sequence of movements performed by a grinding machine during the processes of "dressing", "conditioning" and "machining", respectively. Each is understood to mean. In particular, dressing kinematics is understood as the sequence of movements that engages a dressing tool with a rotating grinding tool in order to dress the grinding tool. Dressing kinematics may include movement of the grinding tool relative to the machine bed of the grinding machine and/or movement of the dressing tool relative to the machine bed. Dressing kinematics are provided by one or more numerically controlled (NC) axes of the grinding machine. ``Conditioning kinematics'' is therefore understood to mean the sequence of movements in which a conditioning tool is engaged with a rotating grinding tool in order to condition the grinding tool, and ``machining kinematics'' is understood to mean the sequence of movements in which a conditioning tool is engaged with a rotating grinding tool in order to condition the grinding tool, and ``machining kinematics'' refers to is understood to mean the sequence of operations in which a rotary grinding tool is engaged with a workpiece in order to do so.

Two kinematics are considered different if the associated movements not only differ in individual parameters such as travel length, velocity, etc., but also differ in the basic motion sequence. For example, the machining kinematics in continuous generation gear grinding using a grinding worm are different from dressing kinematics where the grinding worm is dressed by a rotating dressing wheel. For example, machining kinematics in continuous generation gear grinding involves forced coupling of the rotational speed of the grinding worm and workpiece to meet rotational conditions, whereas dressing kinematics does not involve such forced coupling. . Also, the machining kinematics in interrupted profile grinding using a profile grinding wheel are fundamentally different from the dressing kinematics in dressing the profile grinding wheel using a rotating dressing wheel. For example, machining kinematics require machining one tooth slot before engaging a profile grinding wheel to the next tooth slot. This element is completely absent in dressing kinematics.

According to the invention, the conditioning kinematics is different from the machining kinematics, ie, during conditioning, a different operating sequence is performed than the operating sequence used to machine the workpiece. Preferably, the conditioning tool is clamped on a conditioning device different from the work spindle, i.e. the conditioning is not carried out with the work spindle, as is the case when sacrificial workpieces are used, but separately from the work spindle. It is performed using a conditioning device. The conditioning device can in particular be integrated into or combined with the dressing device.

In particular, the basic shape of the conditioning tool can correspond to the basic shape of a dressing tool that is specifically used for dressing grinding tools, or, if several dressing tools are used, the basic shape of these dressing tools. It can correspond to one of the basic shapes. For example, if a rotating disc-shaped dressing tool is used for dressing, the conditioning tool can also be disc-shaped and have similar dimensions to the dressing tool. The conditioning kinematics can then correspond to the dressing kinematics of this dressing tool.

However, the basic shape of the conditioning tool can also differ from the basic shape of the dressing tool actually used. For example, dressing can be performed using a rotating disc-shaped dressing tool, whereas the conditioning tool is designed as a stationary member, such as a pin, tooth, or rod. Therefore, the conditioning kinematics may differ from the actual dressing kinematics used. However, conditioning kinematics in this case are also kinematics that can also be used for dressing, and in this regard conditioning kinematics also correspond to dressing kinematics in this case.

Preferably, the conditioning tool is made of metal, especially steel, in the area that comes into contact with the grinding tool during conditioning. Preferably, the steel is a steel that has similar properties to the steel from which the work is made. In particular, the steel can be the same type of steel used for the workpiece. In particular, the conditioning tool can accommodate a steel base body of the dressing tool, which is omitted with a hard material coating.

As mentioned above, in some embodiments, the conditioning tool is stationary during the conditioning process. In other embodiments, the conditioning tool rotates during the conditioning process, and this rotation can be up-cut or down-cut relative to the rotation of the grinding tool.

In the case of a rotary conditioning tool, the conditioning tool can have the basic shape of a dressing roll, ie a disc-shaped basic shape. In particular, the conditioning tool can have the shape of a so-called profile roll or foam roll. "Profile roll" is understood to relate to a dressing roll that is arranged to dress a grinding tool in line contact so as to transfer the profile shape of the dressing roll to the grinding tool. Line contact may, for example, occur only in the region of one tooth flank of the grinding tool, or in two adjacent tooth flanks, or may also include the intermediate head region and/or the foot region of the grinding tool. On the other hand, the term "foam roll" is understood as relating to a dressing roll that is provided for dressing the grinding tool in point contact. As already explained, the conditioning tool preferably corresponds to the steel substrate of the dressing roll without a hard material coating.

Whether the conditioning tool is configured to rotate or to be stationary, the conditioning tool is generally capable of making line contact with at least a portion of the machining profile of the grinding tool during the conditioning process. , or may make point contact with a part of the machining profile. If the conditioning tool does not make line contact along the entire machining profile of the grinding tool, the gear grinding machine changes the contact position between the conditioning tool and the grinding tool along the profile of the grinding tool during conditioning. It may be possible to perform relative movements between the tool and the conditioning tool.

As already mentioned, the invention provides that in step c) all workpieces are machined with the same machining parameters, in particular with the same infeed and workpiece spindle axis perpendicular to the workpiece spindle axis. can be machined with the same axial feed rate along. These machining parameters can be selected such that, if step b) is not carried out, thermal damage of the edge zone occurs during machining of at least the first workpiece in step c). This is possible because in step b) conditioning is carried out in such a way that thermal damage of the edge zone strictly no longer occurs during the machining of step c).

Steps a) to c) can be repeated multiple times. Conditioning process b) can be carried out multiple times using the same conditioning tool. Therefore, unlike sacrificial workpieces, conditioning tools do not need to be discarded after a single conditioning process and can be reused multiple times.

The machining of the workpiece in step c) can in particular be carried out by continuous generation gear grinding or by interrupted profile grinding. The grinding tool can therefore be a grinding worm or a profile grinding wheel.

The present invention also provides a gear cutting machine specifically configured to carry out the method disclosed above. This gear cutting machine is
a tool spindle capable of clamping a grinding tool;
at least one workpiece spindle capable of clamping a workpiece;
a dressing device capable of clamping a dressing tool;
a plurality of machine axes for driving the tool spindle, the work spindle and the dressing device and moving them relative to each other;
a control unit that controls the machine axis;
Equipped with

The gear cutting machine is characterized in that it is equipped with a conditioning device different from the work spindle, and the conditioning tool can be clamped onto the conditioning device. The control unit is then configured to control the machine axes such that the processing machine performs a method of the type described above, thereby providing conditioning that preferably corresponds to dressing kinematics, as opposed to machining kinematics. Conditioning is performed through kinematics.

Preferred embodiments of the invention will be explained below on the basis of the drawings. The drawings are for illustrative purposes only and are not to be construed as restrictive.

FIG. 1 is a perspective view of a gear grinding machine according to an embodiment. FIG. 2 shows a section in the region of the dressing device of the gear grinding machine of FIG. 1, in which parts of the gear grinding machine are not shown for reasons of simplicity. FIG. 3 shows the section of FIG. 2, in which a profile grinding wheel is provided as the grinding tool instead of the grinding worm. FIG. 4 is a schematic diagram showing a grinding worm engaging a workpiece. FIG. 5 is a schematic diagram showing a profile grinding wheel engaging a workpiece. FIG. 6 is a flowchart of the method according to the invention.

[Exemplary processing machine design]
FIG. 1 shows an example of a processing machine that hardens and finishes gears by generating gear grinding. The horizontal spatial direction is designated by X and Y, and the vertical spatial direction (direction of gravity) is designated by Z. The processing machine has a machine bed 100, on which an infeed slide 210 is arranged so as to be movable along the infeed direction X1. The feed direction X1 corresponds to the horizontal spatial direction X. A tower-like tool carrier 200 is mounted on an infeed slide 210 so as to be pivotable about a vertical pivot axis C1. The vertical pivot axis C1 will hereinafter be referred to as the C1 axis. A feed slide 220 is arranged on the tool carrier 200 so as to be movable along the axial feed direction Z1. The feeding direction Z1 corresponds to the vertical spatial direction Z. The feed slide 220 holds a tool head 300 that is pivotable relative to the feed slide 220 about a horizontal pivot axis A1. The horizontal pivot axis A1 will hereinafter be referred to as the A1 axis. The A1 axis is parallel to the feeding direction X1. A tool spindle 310 is arranged on the tool head 300 so as to be movable along the shift direction Y1. The shift direction Y1 is perpendicular to the A1 axis and has an angle with respect to the axial feed direction Z1 according to the turning angle of the tool head 300 around the A1 axis. A grinding tool 320 in the form of a grinding worm is clamped onto the tool spindle 310 for rotation about the tool spindle axis B1 (see FIGS. 2-5). The tool spindle axis B1 is parallel to the shift direction Y1.

A dressing device 400 is placed on the machine bed 100. On the side of the tool carrier 200 facing away from the dressing device 400, the work spindle 500, which is only partially visible in FIG. The rotated workpiece 510 is rotated (see FIGS. 4 and 5). The tool carrier 200 is pivotable 180° about the C1 axis between a machining position and a dressing position. In the machining position of tool carrier 200, grinding tool 320 can be engaged with workpiece 510 (see FIGS. 4 and 5). In the dressing position, the grinding tool 320 can be engaged with a dressing tool of a dressing device 400, which will be described in more detail below (see FIGS. 2 and 3). In FIG. 1, tool carrier 200 is shown in a dressing position.

A machine control 600, shown only symbolically, receives signals from sensors in the processing machine and controls the linear and pivot axes of the processing machine, tool spindle, workpiece spindle, and dressing device.

The machine concept according to FIG. 1 is disclosed in US Pat. No. 5,857,894. A corresponding machine is available under the designation RZ 400 from Reishauer AG, Wallisellen, Switzerland.

[Dressing device and conditioning device]
In FIG. 2 a section of the processing machine of FIG. 1 is shown from a different perspective. Some parts of the processing machine have been omitted for a clearer explanation.

Although the grinding tool 320 is shown as free floating in FIG. 2, it is understood that the grinding tool is still clamped to the tool spindle 310 as shown in FIG. For the discussion below, it is assumed that the grinding tool 320 comprises an abrasive body made of vitrified bonded cBN.

In particular, FIG. 2 shows the structure of a dressing device 400. The dressing device 400 comprises a first dressing spindle 410 which is pivotable relative to the machine bed about a vertical axis C_P1 and linearly movable along two orthogonal horizontal directions X_P, Y_P. A pivoting drive 411, a first linear drive 412 and a second linear drive (not visible in FIG. 2) serve this purpose. A disc-shaped dressing tool 415 is rotationally clamped onto the first dressing spindle 410 . The dressing device 400 further comprises a second dressing spindle 420 which is pivotable relative to the machine bed about a vertical axis C_P2 by means of a pivot drive 421. A second disc-shaped dressing tool may be rotationally clamped onto the second dressing spindle 420.

In accordance with the invention, instead of a dressing tool, a disc-shaped first conditioning tool 425 is clamped onto the second dressing spindle 420 . Additionally or alternatively, a stationary second conditioning tool 416 may be provided. The stationary conditioning tool 416 is held in a holder 417, which in the example of FIG. 2 is stationarily arranged on the housing of the first dressing spindle 410.

Accordingly, in the context of the present invention, the dressing device 400 performs the combined function of a dressing device and a conditioning device. Strictly speaking, only the first dressing spindle 410 with the clamped dressing tool 415 forms the actual dressing device, the second dressing spindle 420 with the conditioning tool 425 clamped and the holder 417 with the stationary conditioning tool 416 and form a conditioning device.

Grinding tool 320 selects each of three dressing or conditioning tools 415, 416, and 425 by providing motion relative to X1, Y1, Z1, A1, X_P, Y_P, C_P1, and C_P2 using the NC axes. can be engaged with each other.

[Grinding tool in the form of profile grinding wheel]
While the grinding tool 320 in FIG. 2 is a grinding worm, FIG. 3 shows the use of a grinding tool 321 in the form of a profile grinding wheel. All considerations described herein apply mutatis mutandis to this type of grinding tool. If a profile grinding wheel is used, the term "tangential feed direction" is usually used for direction Y1 instead of the term "shift direction".

[Dressing process and conditioning process]
To dress the grinding tool 320 or 321, the rotating grinding tool 320, 321 is first engaged with the dressing tool 415, which is also rotating. This creates or restores the desired contour of the grinding tools 320, 321 and sharpens the grinding tools 320, 321.

The rotating grinding tools 320, 321 are then replaced with the rotating conditioning tool 425 and/or the stationary conditioning tool 425, as described above, in order to avoid or at least reduce undesirable cutting behavior of the grinding tools 320, 321 dressed in this way. Conditioning tool 416 is engaged. Conditioning is carried out until it is ensured that no thermal damage occurs in the edge zone of the workpiece during machining of subsequent workpieces, even if machining is carried out with the same technical parameters for all workpieces. Ru.

[Dressing tools and conditioning tools]
Other types of dressing and conditioning tools may be used instead of the types of dressing and conditioning tools shown in FIGS. 1-3. Accordingly, the dressing and conditioning device can be configured differently.

Dressing tool 415 can be any dressing tool suitable for dressing vitrified bonded cBN abrasive bodies. Such dressing tools are known in the prior art in various embodiments. Such dressing tools can be used for various methods of dressing.

For example, it is known that dressing of the grinding worm can be carried out in line contact between the dressing tool and the grinding tool in order to map the profile of the dressing tool onto the profile of the grinding tool. This is called "profile dressing." If the dressing tool rotates, it is referred to as a "profile roll". Depending on the dressing tool and dressing device, during profile dressing, each tooth flank of the worm gear may be dressed individually, both tooth flanks of the worm gear may be dressed simultaneously, or two or more flanks of the multi-start grinding worm may be dressed. The tooth surface of the worm gear may be dressed at the same time. In addition to the tooth surfaces, it is also possible to dress the tip and/or root areas of the worm gear simultaneously or successively. The same or different dressing tools may be used for this purpose (see, for example, US Pat. No. 6,234,880).

It is also known to dress the grinding worm with point contact, whereby the dressing tool is guided line by line along the tooth flank of the grinding worm. This is called "foam dressing." If the dressing tool rotates, it is referred to as a "foam roll".

Mixed configurations are also known in which parts of the profile are dressed with line contact and other parts with point contact, using different dressing tools or different regions of the same dressing tool (e.g. US Pat. No. 6,012,972). ).

Therefore, numerous designs of dressing tools exist. For example, like the dressing tool 415, a disc-shaped dressing tool (dressing roll) that is driven to rotate around a dressing tool axis for dressing is known. In addition, dressing tools often have a disk-shaped base body made of steel, for example with an abrasive coating of diamond particles. On the other hand, other types of dressing tools are configured to be stationary. Such dressing tools can also have a steel substrate coated with an abrasive material.

Different types of dressing methods and corresponding dressing tools are also known as dressing profile grinding wheels. In particular, the profile grinding wheel can also be dressed with line contact or point contact. This can also be done with a rotating disc-shaped dressing tool of the type of dressing tool 415 or with a stationary dressing tool. The dressing tool can have a steel base and an abrasive coating.

Equally diverse configurations of the conditioning processes and conditioning tools used for this purpose are possible. Conditioning of the grinding tool can also be performed with line or point contact. The conditioning tool can be configured to rotate or be stationary. In particular, the conditioning tool can be formed by a steel base of the dressing tool, omitting an abrasive coating, so that the grinding tool is directly conditioned by the steel of the base.

The conditioning tool can be of the same type as the dressing tool. For example, both the dressing tool and the conditioning tool can be disk-shaped tools that are rotated during dressing or conditioning. However, the conditioning tool may differ from the dressing tool. For example, a dressing tool can rotate while a conditioning tool is stationary.

The decisive factor is that the conditioning is carried out not by a sacrificial workpiece that is clamped onto the workpiece spindle for conditioning, but by a separate conditioning tool. The conditioning tool is not clamped onto the workpiece spindle and the conditioning is not performed by kinematics that correspond to the kinematics used for machining the workpiece, rather the conditioning corresponds to the kinematics of a typical dressing operation. It is performed by kinematics. Although the kinematics used for conditioning may differ from the actual kinematics used for dressing (e.g., because the dressing and conditioning tools are not the same), they are still the kinematics that may be used for dressing. be.

In the example of FIGS. 1-3, the same axis of motion that can also be used for dressing can be used for conditioning. These axes of motion include axes X_P, Y_P, C_P1, and/or C_P2. These axes are pure dressing and conditioning axes, not related to machining of the workpiece. It is therefore clear that the sequence of operations during conditioning in the example of FIGS. 1-3 is completely different from that during machining of the workpiece.

[Workpiece machining]
After conditioning, the workpiece is machined. For completeness, this is shown in FIG. 4 as an example of continuous generation gear grinding and in FIG. 5 as an example of interrupted profile grinding.

In the example of FIG. 4, grinding tool 320 is a grinding worm that rotationally engages workpiece 510. In the example of FIG. At the same time, the workpiece 510 rotates around the workpiece spindle axis C' at a rotational speed that has a predetermined rotational speed ratio to the rotational speed of the grinding tool 320. This rotational engagement is established electronically by machine control 600. The grinding tool 320 advances simultaneously and continuously over the entire width of the workpiece along the feed direction Z1 and, if necessary, shifts along the shift direction Y1. It is clear that this kinematics is significantly different from the kinematics used for dressing and conditioning.

In the example of FIG. 5, grinding tool 321 is a profile grinding wheel. The rotary grinding tool 321 is sequentially inserted into each tooth groove of the workpiece 510 to machine the tooth groove. During machining of the tooth groove, the workpiece 510 is stationary and the grinding tool 321 is continuously advanced along the feed direction Z1 over the entire width of the workpiece. The workpiece is then rotated to machine the next tooth space. It is clear that this kinematics is also significantly different from the kinematics during dressing and conditioning.

[flowchart]
The method described above is summarized in the form of a flowchart in FIG. In step 701, the grinding tool is dressed. At step 702, the grinding tool is conditioned. Next, in step 703, the workpiece is machined. If the grinding tool becomes worn enough to require reshaping and/or resharpening, steps 701 and 702 are performed again.

[Other transformations]
The present invention is not limited to the above embodiments, and further modifications are possible. In particular, the invention is not limited to any particular machine design and can be used with any gear grinding machine that allows for both dressing and conditioning.

100 Machine bed 200 Tool carrier 210 Feed slide 220 Feed slide 300 Tool head 310 Tool spindle 320, 321 Grinding tool 400 Dressing device 410 Dressing spindle 411 Swivel drive 412 Linear drive 415 Dressing tool 416 Conditioning tool 417 Holder 420 Dressing spindle 421 Swing drive unit 425 Conditioning tool 500 Work spindle 510 Work 600 Machine control unit 701 to 703 Procedure steps X, Y, Z Coordinates X1 Feed direction Y1 Shift direction Z1 Axial feed direction A1 Tool head rotation axis C1 Tool carrier rotation axis C ' Work spindle axis X_P, Y_P Dressing/conditioning displacement direction C_P1, C_P2 Dressing/conditioning rotation axis

Claims (15)

A method of machining a workpiece (510) in a gear grinding machine using a grinding tool (320, 321) comprising vitrified bonded abrasive grains made of superabrasive material, in particular cBN, comprising:
a) dressing the grinding tool (320, 321);
b) conditioning the dressed grinding tool (320, 321) so as to provide a desired wear condition of the grinding tool (320, 321), the gear grinding machine having conditioning kinematics. Steps to execute and
c) machining a pre-toothed workpiece (510) using the dressed and conditioned grinding tool (320, 321), the gear grinding machine performing machining kinematics; step and
including;
The method, characterized in that the conditioning kinematics are different from the machining kinematics. The method of claim 1, wherein the conditioning kinematics correspond to dressing kinematics of a dressing tool (415). The processing machine includes a conditioning device (417, 420) to which a conditioning tool (416, 425) is clamped, and the conditioning in step b) is performed using the conditioning tool (416, 425),
The processing machine includes a work spindle (500) on which the work (510) is clamped in step c),
3. A method according to claim 1 or 2, wherein the conditioning device (417, 420) is different from the work spindle (500). 4. The method of claim 3, wherein the conditioning tool (416, 425) has a basic shape different from the basic shape of the workpiece (510). 5. The method of claim 4, wherein the conditioning tool (416, 425) has a basic shape that corresponds to the basic shape of the dressing tool (415). Method according to any one of claims 1 to 5, wherein the conditioning tool (416, 425) is made of metal, in particular steel, in the area that contacts the grinding tool (320, 321) during conditioning. . A method according to any one of claims 1 to 6, wherein the grinding tool (320, 321) rotates during the conditioning step and the conditioning tool (416) is stationary during the conditioning step. . The grinding tool (320, 321) is rotated during the conditioning step, and the conditioning tool (425) is in an up-cut or down-cut direction with respect to the grinding tool (320, 321) during the conditioning step. The method according to any one of claims 1 to 6, wherein the method is rotated to The method according to claim 8, wherein the conditioning tool (425) corresponds to a metal substrate of a dressing roll, having the basic shape of a dressing roll, in particular a profile roll or a foam roll, preferably without a hard material coating. . A method according to any of the preceding claims, wherein the conditioning tool (416, 425) makes line or point contact with the grinding tool (320, 321) during the conditioning step. The gear grinding machine is configured such that during conditioning, the contact position between the conditioning tool (416, 425) and the grinding tool (320, 321) changes along the profile of the grinding tool (320, 321). 11. The method according to any of the preceding claims, further comprising performing a relative movement between the grinding tool (320, 321) and the conditioning tool (416, 425). all workpieces (510) in step c) are machined with the same machining parameters, in particular infeed rate and axial feed rate;
said machining parameters are selected such that, if step b) is not performed, thermal damage of the edge zone occurs during machining of at least the first workpiece (510) in step c);
12. A method according to any one of claims 1 to 11, wherein in step b) the conditioning is carried out such that no thermal damage of the edge zone occurs during the machining in step c). Method according to any of the preceding claims, wherein the conditioning step b) is carried out multiple times using the same conditioning tool (415, 426). A method according to any of the preceding claims, wherein the grinding tool (320, 321) is a grinding worm or a profile grinding wheel. A gear cutting machine,
a tool spindle (310) capable of clamping a grinding tool (320, 321);
at least one work spindle (500) capable of clamping a work (510);
a dressing device (400) capable of clamping at least one dressing tool (415);
A plurality of machine axes (X1, Y1, Z1, A1, C1, C ', X_P, Y_P, C_P1, C_P2) and
a control unit (600) that controls the mechanical axes (X1, Y1, Z1, A1, C1, C', X_P, Y_P, C_P1, C_P2);
Equipped with
The gear cutting machine comprises a conditioning device (417, 420) different from the work spindle (500), and at least one conditioning tool (416, 425) is clamped on the conditioning device (417, 420). is possible,
The gear cutting machine, characterized in that the control unit is configured to control the machine axes such that the machine carries out the method according to any one of claims 1 to 14. .

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